Generally, a fluid body such as an aircraft wing includes flaps to increase a lift coefficient of the wing. In known upper surface blowing (USB) systems, blown flaps employ efflux (e.g., air and/or exhaust or an exhaust stream) of engines to provide lift for short take-off and landing (STOL) or extremely short take-off and landing (ESTOL) maneuvers. The engines used in these systems may be disposed above or beneath the wings. If the engines are disposed above the wings, the flaps are upper surface blown flaps and the efflux of the engines interacts with upper surfaces of the wings and the flaps to provide lift. For example, the efflux may follow a curvature of the upper surfaces of the wings and the flaps to provide lift.
Known systems used for STOL or ESTOL maneuvers may allow control and/or variation of lift, but may be limited (e.g., limited in terms of degrees of freedom) in directional control of an aircraft during such maneuvers. In particular, as these known systems generate the lift necessary for STOL or ESTOL maneuvers, typical control effectors such as elevator and rudders become less effective due to decreased dynamic pressure experienced by the control effectors. To counteract this reduced effectiveness, control surfaces of USB aircraft are often made to be relatively large, thereby requiring increased weight and/or decreased efficiency of these aircraft. These relatively large control surfaces may result in diminished performance during cruise, for example.